Newbie to site.. Navien NCB240 went up in smoke this morning

lawandorder815

So my Navien NCB240 went up in smoke. Wife said no hot water. Went downstairs to basement and found the cabinet burned up, opened the cabinet and the heat exchanger had visible flame marks, sight glass was melted, wiring melted near heat exchanger and some piles of plastic where the venting is also melted before it shut down. Called installer no response since I left messages all day. Never even heard of something like this. Unit was installed in 2017.Any thoughts or help??

Mad Dog_2

Was it serviced annually? Mad Dog

Mad Dog_2

You should be on the phone with Navien....Mad Dog

SuperTech

Unfortunately this is not uncommon. Naviens are known to self destruct in a few different ways. I've seen them meltdown in similar fashion, even when well maintained. I had two leak water from the heat exchanger 3 months after they were installed. Naviens are known to leak flue gas inside the cabinet, causing the exhaust to be recirculated into the combustion air intake. They definitely have their problems. The new fire tube combis are supposed to be better but I would be happy if I never saw another Navien product during my service calls ever again.

lawandorder815

was cleaned and serviced September of 2022 when they replaced the ignitor which was throwing codes

Im not getting a warm and fuzzy feeling on this. It sounds like Navien has issues.

GroundUp

The ol' KyungDong certification tends to be just that. This is an incredibly common point of failure with these units unfortunately, I've seen it several dozen times in the past few years. The good thing is that Navien is usually pretty good about warranty and sending a replacement unit, but it'll often take weeks to get taken care of and you'll be on the hook for labor as well.

EBEBRATT-Ed

It would be nice if we were not buying "Kyung Dong" boilers. I would prefer anything made in the USA.

Navien has lots of issues.

dko

The Buderus GB boilers have been using kyungdong "navien" heat exchangers for ages.
Navien units in Korea are the highest rated and least problems.

Something went wrong between manufacturing for the US Market, installation issues, water quality, etc.. Especially the water tube hx. I hardly hear issues with the fire tube.

Sad really

EBEBRATT-Ed

The reoccurring Navien issue I keep hearing about is leaking flue gas gaskets causing flue gas recirculating.

I was just wondering how MOD CON boilers are tested as far as water temperature is concerned. I think most MOD CONs out of Europe are limited to a max temp of 177F ????

Seems like I remember something about that

I wonder if continued operation at the high end of the scale is an issue??

I know that is what is driving/has driven the change from PVC pipe for the flue to other systems higher temp operation. If the water temp or air temp is high (furnaces) the flue gas temp will also rise.

GGross

Undoubtedly there was evidence of this when the igniter was replaced 2 years ago, it didn't happen overnight, and it is too bad it was missed. I have seen a similar issues here on the wall, and a few with other brands in the same general location. One of these I saw on the wall, the unit was still under warranty and it sounded like Navien was going to assist with warranty. I'm no Navien fan but in general the tankless units are up there with other brands. everon co (kyongdong everon co) is a South Korean company, much as we all prefer US made components, it's not like South Korea doesn't have similar regulations to us, in many cases they have more strict regulations. I would imagine this issue started with a defect however, and assuming you are in warranty period Navien will likely want to assist, this is a heat exchanger defect and I think most of those units have a 10 year warranty for that. You may need to contact their tech support yourself if you have issues finding a contractor to process the warranty, many don't want to do that unless they installed the equipment

lawandorder815

So finally found someone to look at it after a phone call to Navien Support. Sent them photos as well as repair person who came out two days ago. Heat exchanger was leaking a bit on the bottom which was new. The last time it was serviced there were no leaks because the tech specifically checked that and the tested the flue gasses etc. Longer story short is Navien has ok'd a new model replacement unit which is being installed tomorrow. I m going to have to pay labor and Navien is making him put in a low water cutoff and a different styled manifold which im not sure of at this point

.

EBEBRATT-Ed

Thanks for letting us know.

Glad that Navien stepped up.

keep up with the service and document everything in case you have problems in the future.

maybe Navien has corrected some of there issues.

Mad Dog_2

Glad it's working out for you. Navien stands by the product. Mad Dog 🐕

lawandorder815

New unit is in. Had to upgrade the manifold and some other piping. But we shall see. I already scheduled him to come back in November to run through everything on it and get the radiant heat set and test run.